This invention relates to a motor cooling path and thrust bearing load design.
Conventionally, electric motors have a rotor assembly driven by a stator. Motors subject to high heat may use air bearings, particularly, journal and thrust bearings. The air bearings and stator of an electric motor have been cooled using two airflow paths that are separate from one another. That is, the airflow paths have separate inlets and separate outlets. As a result of using separate flow paths, the bearings are subject to different loads based upon the different pressures in the flow paths that are exerted on the rotor assembly, bearings, and seals. The imbalanced loading on the rotor assembly increases the load on the thrust bearing, which is undesirable.
It is desirable to balance the loads so that the net axial load on the thrust bearing is zero. Typically, the journal bearings used to support the rotor assembly are of an unequal size to compensate for the imbalance of loads resulting from the different pressures.
The separate flow paths are conventionally separated from one another using numerous, unequally-sized seals. The different bearings and seals add cost and complexity to the assembly of the motor.
What is needed is a single source for the bearing and motor cooling to minimize cost and complexity. What is needed also is a load design for the thrust bearings that minimizes cost and reduces complexity assembling the motor. It is desirable not to use high pressure (compressed) air.